Disable Mobile settings in one condition.

If there is no active subscription and esim is unsupported, disable
this preference.

Bug: 129143739
Test: RunSettingsRoboTests
Change-Id: I5f8b0d95df8764a3a505aae5e26df42e9412c021

src/com/android/settings/network/MobileNetworkSummaryController.java

@@ -137,6 +137,8 @@ public class MobileNetworkSummaryController extends AbstractPreferenceController
                     startAddSimFlow();
                     return true;
                 });
+            } else {
+                mPreference.setEnabled(false);
             }
         } else {
             // We have one or more existing subscriptions, so we want the plus button if eSIM is